The present invention relates generally to a superconductive magnet used to generate a high magnetic field as part of a magnetic resonance imaging (MRI) diagnostic system, and more particularly to such a magnet having a compact design for inexpensively imaging specific parts of the human body, such as the brain.
MRI systems employing superconductive magnets are used in various fields such as medical diagnostics. Known superconductive magnets include liquid-helium cooled and cryocooler-cooled superconductive magnets. Typically, for a cryocooler-cooled magnet, the superconductive coil assembly includes a superconductive main coil surrounded by a thermal shield surrounded by a vacuum enclosure. A cryocooler coldhead is externally mounted to the vacuum enclosure, has its first stage in thermal contact with the thermal shield, and has its second stage in thermal contact with the superconductive main coil.
Superconductive magnets have been mentioned in a sales brochure which claim a helmet design (with eye opening) for MRI brain imaging within a 10 centimeter-diameter spherical imaging volume of 2 Tesla having a pre-shim inhomogeneity of 10 parts per million (ppm) and a bore diameter of 20 centimeters. However, such designs have not been disclosed.
Known superconductive magnets include those having a large, tubular-shaped superconductive coil assembly with one or more longitudinally spaced-apart main coils carrying an equal electric current in a first direction for generating a high magnetic field within the spherical imaging volume of the magnet's bore. Such whole-body magnets provide an expensive way for MRI imaging of the brain.
What is needed is a relatively inexpensive superconductive magnet designed for high magnetic field MRI imaging of the human brain.